I'm embarking on a set of experiments with different grounds. In the past year or so, I've been using Blick Master Gesso (three coats) on hardboard, but I'm finding it a bit too slick and unabsorbent for my tastes.
So, here's the first test: Winsor & Newton Oil Painting Ground (two coats) on hardboard. It seems pretty right to me - just enough absorbency and roughness. I didn't sand it at all. The downside is, it uses petroleum distillates.
(For the record, I'm painting alla prima, wet-into-wet, using Gamblin paint with a bit of Gamsol to thin and a tad of Galkyd to keep paint creamy.)